System, method and apparatus for establishing interactive media session based on IP multimedia subsystem

ABSTRACT

A method and system for establishing an interactive media session based on IP Multimedia Subsystem, including: a terminal adapted to initiate an interactive media session request and receive a media session response; a serving-CSCF adapted to trigger the request to the application server according to a triggering rule and route the message; a proxy-CSCF adapted to forward the request and the response between the terminal and the serving-CSCF; an application server adapted to process the service request; a media control entity adapted to control resource allocation of the media carrier entity; and a media carrier entity adapted to allocate address ports for RTSP connection and RTP connection with the terminal. The present invention can be applied to a NGN network where the carrier and control are separated to improve the media delivery efficiency.

CROSS-REFERENCE TO RELATED APPLICATIONS

The application is a continuation of U.S. patent application Ser. No.12/192,985, filed on Aug. 15, 2008, which is a continuation ofInternational Patent Application No. PCT/CN2007/000557, filed on Feb.15, 2007, which claims priority to Chinese Patent Application No.200610033768.4, filed on Feb. 18, 2006, all of which are herebyincorporated by reference in their entireties.

FIELD OF THE INVENTION

The present invention relates to a system and a method for establishinga session, and more particularly to a system, a method and an apparatusfor establishing an interactive media session based on IP MultimediaSubsystem (IMS).

BACKGROUND OF THE INVENTION

With the development of technologies, people are no longer content withinactively watching a program on a TV or computer, rather, they preferto control the playing of the program, for example, to skip theadvertisement using “fast forward” or repeatedly watch an exciting sceneusing “rewind”. Such kind of media applications that involve interactivecontrol from the users are referred to as interactive media services.

Currently, interactive media services are widely used, such as thecontent-on-demand application in digital TV which allows the user toarbitrarily control the playing procedure, and e-learning applicationwhich allows a student to review a certain part of what the teacher justtaught at any time.

In the interactive media service, the user is allowed to perform userinteractive control operations such as pause, fast forward, rewind, etc.Currently, these interactive controls are carried out through a RealTime Stream Protocol (RTSP), which defines a message mechanism and datapacket for the interactive controls between a media sender and receiver.Generally, the media receiver is a terminal, such as a television, acomputer, a mobile phone, a PDA, etc., and the media sender is a datasource for storing the media, usually a media server.

For the media sender and receiver to transmit an interactive controlsignaling, a channel for delivering the signaling, i.e., an RTSPconnection, must be established. The connection can be established usingeither Transport Control Protocol (TCP) or User Datagram Protocol (UDP),and the default port number is 554. Meanwhile, a channel for deliveringa media needs to be set up, which is typically a Real-time TransportProtocol (RTP) connection. The RTP connection is generally establishedthrough UDP. In a conventional network environment, the media sender andreceiver establish the RTSP connection first, and then negotiate theaddress for RTP connection using a SETUP message over the RTSPconnection. When the negotiation on the address is finished, the mediareceiver notifies through a PLAY message the media sender to startplaying the media stream.

IP Multimedia Subsystem (IMS) uses an IP grouping domain as a carrierchannel for controlling signaling and media delivery, and uses SessionInitiation Protocol (SIP) as a call control signaling, therebyseparating service management, session control and carrier access fromeach other.

The IMS network architecture having above separate feature providesnecessary conditions for fast deployment and uniform control of variousservices, which include not only session services but also mediaservices. In the IMS network environment, uniform service management isrealized through an application server. In the media serviceapplications, various specific media applications can be deployed indifferent media application servers, such as a content-on-demandapplication server, a radio-television application server, etc.Meanwhile, the uniform service control can be conducted by entity andmechanisms at the session control layer.

In the existing system and method for establishing interactive mediasession, the terminal establishes an RTSP connection with the mediaserver directly and then negotiates an address for RTP connection usingthe RTSP connection.

In the Next Generation Network (NGN) environment, the carrier functionis independent of the control function, and a media server can bedisassembled into a media control entity and a media carrier entity. TheRTSP connection is established between the terminal and the mediacarrier entity. However, when the terminal and the media carrier entitynegotiate the address for RTP connection over the RTSP connection, themedia control entity cannot control the media carrier entity because thenegotiation messages do not go through the media control entity.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide a system, a method and anapparatus for establishing an interactive media session based on IMS,for use in a NGN network where the bearer and controller are required tobe separated with each other.

An embodiment of the present invention provides a method forestablishing an interactive media session based on an IP MultimediaSubsystem, including:

-   -   receiving, by a media control entity, an interactive service        request initiated by a terminal;    -   controlling, by the media control entity, a media carrier entity        to negotiate an address port for RTSP connection and an address        port for RTP connection to communicate with the terminal; and    -   establishing an RTSP connection for interactive control and an        RTP connection for media stream delivery between the terminal        and the media carrier entity.

An embodiment of the present invention provides a method forestablishing an interactive media session based on IP MultimediaSubsystem, including:

-   -   receiving, by a MRF, an interactive service request initiating        by a terminal;    -   negotiating, by the MRF, an address port for RTSP connection and        an address port for RTP connection to interact with the        terminal;    -   establishing an RTSP connection for interactive control based on        the address port for RTSP connection between the terminal and a        media control entity of the MRF; and    -   establishing an RTP connection for media stream delivery based        on the address port for RTP connection between the terminal and        a media carrier entity of the MRF.

An embodiment of the present invention provides a method forestablishing an interactive media session based on IP MultimediaSubsystem, including:

-   -   receiving, by a media control entity, an interactive service        request initiated by a terminal via an application server;    -   negotiating, by the application server, an address port for RTSP        connection to communicate with the terminal and establishing an        RTSP connection with the terminal for interactive control;    -   negotiating, under the control of the media control entity, by a        media carrier entity, an address, port for RTP connection to        communicate with the terminal; and    -   establishing an RTP connection for media stream delivery between        the terminal and the media carrier entity.

An embodiment of the present invention provides a method forestablishing an interactive media session based on IP MultimediaSubsystem, including:

-   -   receiving, by a media control entity, an interactive service        request initiated by a terminal;    -   negotiating, under the control of the media control entity, by a        media carrier entity, an address port for RTP connection to        communicate with the terminal;    -   establishing an RTP connection for media stream delivery between        the terminal and the media carrier entity;    -   delivering a SIP message to an AS by the terminal, wherein the        SIP message carries media interactive control information;    -   acquiring, by the AS from the SIP message, the media interactive        control information and converting the media interactive control        information to an RTSP message; and    -   interacting, between the AS and a MRF, through RTSP messages to        exert interactive media control between a user and the MRF.

An embodiment of the present invention provides a method forestablishing an interactive media session based on IP MultimediaSubsystem, including:

-   -   receiving, by a media control entity, an interactive service        request initiated by a terminal;    -   negotiating, by a media carrier entity, an address port for RTP        connection to communicate with the terminal under the control of        the media control entity;    -   establishing an RTP connection for media stream delivery between        the terminal and the media carrier entity;    -   delivering a SIP message to the media control entity by the        terminal, the SIP message carries media interactive control        information;    -   acquiring, by the media control entity from the SIP message, the        media interactive control information and converting the media        interactive control information to an H.248 message; and    -   controlling, by the media control entity, the media carrier        entity to interact, so as to realize media interactive control        through the H.248 message.

An embodiment of the present invention provides a method forestablishing an interactive media session based on IP MultimediaSubsystem, including:

-   -   receiving, by a media stream server which finally provides        service, an interactive service request initiated by a terminal;    -   negotiating, under the control of a controller inside the media        stream server, by the media stream server, an address port for        RTP connection to communicate with the terminal;    -   establishing an RTP connection for media stream delivery between        the terminal and the media stream server;    -   providing, by the terminal, media interactive control        information through a SIP message extension; sending, by the IMS        network, the SIP message to an MRF; and    -   converting, by the MRF, the media interactive control        information carried in the SIP message to an RTSP message and        exerting media interactive control with a media server already        deployed in the network to realize the media interactive control        between the terminal and the media stream server which finally        provides service.

An embodiment of the present invention provides a system forestablishing an interactive media session based on IP MultimediaSubsystem, comprising an application server, a media control entity anda media carrier entity, wherein the media carrier entity is incommunication with a terminal, wherein

-   -   the terminal is adapted to initiate an interactive service        request and establish a Real Time Stream Protocol (RTSP)        connection and a f (RTP) connection;    -   the application server is adapted to process the service        request;    -   the media control entity is adapted to control resource        allocation of the media carrier entity; and    -   the media carrier entity is adapted to allocate, under the        control of the media control entity, address ports for an RTSP        connection and an RTP connection, and establish the RTSP        connection and the RTP connection with the terminal.

An embodiment of the present invention provides a system forestablishing an interactive media session based on IMS MultimediaSubsystem, comprising: an application server, a media control entity, amedia carrier entity, wherein the media carrier entity is incommunication with a terminal, wherein

-   -   the terminal is adapted to initiate an interactive service        request and establish a Real Time Stream Protocol (RTSP)        connection and a Real-time Transport Protocol (RTP) connection;    -   the application server is adapted to process the service        request;    -   the media control entity is adapted to control resource        allocation of the media carrier entity, and allocate an address        port for RTSP connection to establish an RTSP connection with        the terminal; and    -   the media carrier entity is adapted to allocate an address port        for RTP connection under the control of the media control entity        and establish an RTP connection with the terminal.

An embodiment of the present invention provides a media resource controldevice, including:

-   -   a first interactive unit, adapted to receive a request delivered        by a terminal, and as a response, according to the information,        carried in the request, about address ports of the terminal for        establishing RTSP and RTP connections, return to the terminal        address ports for establishing RTSP and RTP connections with the        terminal; and    -   a control unit, adapted to control a media carrier entity to        allocate address ports for establishing RTSP connection and RTP        connection with the terminal, according to the request received        by the first interactive unit.

An embodiment of the present invention provides a media resource controldevice, including:

-   -   a first interactive unit, adapted to receive a request delivered        by a terniinal, and as a response, return to the terminal        address ports for establishing connections with the terminal;    -   a port allocating unit, adapted to allocate a local address port        for RTSP connection based on the request received by the first        interactive unit; and    -   a control unit, adapted to control a media carrier entity to        allocate an address port for establishing RTP connection with        the terminal, based on the request received by the first        interactive unit.

An embodiment of the present invention provides a media resourceprocessing device, including:

-   -   a port allocating unit, adapted to allocate a local address port        for RTSP connection and/or for RTP connection with a terminal        under the control of a media control entity;    -   a delivering unit, for delivering the information about address        ports for RTSP and RTP connection to the media control entity.

In embodiments of the present invention, the resource allocation for theRTSP and RTP connection of the media server is performed under thecontrol of the media control entity, thus the media control entity cancontrol and record the resource information, such as the address port,of the media carrier entity. Therefore, the present invention can beapplied to the NGN network environment where the carrier and control arerequired to be separated. Meanwhile, since the RTP media connection isestablished between the terminal and the media carrier entity, the mediadelivery efficiency can be ensured.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a network architecture diagram of the system for establishinginteractive media session based on IMS according to an embodiment of thepresent invention;

FIG. 2 is a flow chart of establishing interactive media session basedon IMS according to embodiment 1 of the present invention;

FIG. 3 is a flow chart of establishing interactive media session basedon IMS according to embodiment 2 of the present invention;

FIG. 4 is a flow chart of establishing interactive media session basedon IMS according to embodiment 3 of the present invention;

FIG. 5 is a flow chart of establishing interactive media session basedon IMS according to embodiment 4 of the present invention;

FIG. 6 is a schematic diagram of a media resource control deviceaccording to embodiment 1 of the present invention;

FIG. 7 is a schematic diagram of a media resource control deviceaccording to embodiment 2 of the present invention; and

FIG. 8 is a schematic diagram of a media resource processing deviceaccording to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

During establishing an interactive media session in the IMS networkenvironment, it is necessary to obey the principle of separating thecontrol function and the carrier function of the NGN. All the controlfunctions for establishing the interactive media session, such asnegotiating the port necessary for establishing the media connection,must be performed at a control layer. The final media connection at acarrier layer is established between the terminal and network carrierentity (e.g. an application server having media content stored thereon).

In the IMS network environment, a media control entity at a controllayer corresponds to the Multimedia Resource Function Controller (MRFC)of the IMS network architecture, and a media carrier entity at a carrierlayer corresponds to the Multimedia Resource Function Processor (MRFP)of the IMS network architecture. Thereby, in the IMS networkenvironment, when interactive control connection and media connectionare established between a terminal and a media server, a signalingrelated control has to be exerted by the MRFC, and the final mediaconnection is established between the terminal and the MRFP.

As shown in FIG. 1, a system for establishing an interactive mediasession based on IMS according to the present invention includes aterminal 15, a proxy Call Session Control Function (CSCF) 13, aserving-CSCF 12, an application server 11, MRFC 14 and MRFP 16. Theterminal 15 is adapted to initiate an interactive media session requestand receive a media session response; the proxy-CSCF 13 is adapted toforward requests and responses between the terminal 15 and theserving-CSCF 12; the serving-CSCF 12 is adapted to route and trigger therequest to the application server 11 according to a triggering rule; theapplication server 11 is adapted to process a media session request; theMRFC 14 is adapted to control the resource allocation of MRFP 16, suchas the port number allocation; the MRFP 16 is adapted to allocateresource information such as an address port for RTSP connection and anaddress port for RTP connection under the control of the MRFC 14, andestablish an RTSP connection and an RTP connection.

Further, as required, the MRFC 14 may act as an RTSP proxy, forward theRTSP message between the terminal 15 and the MRFP 16, or perform SIPencapsulation/decapsulation towards an RTSP message.

As required, the MRFP 16 may also perform SIPencapsulation/decapsulation towards an RTSP message.

Further, as required, the application server 11 may receive controlmessages from a personal VCR (Video Cassette Recorder) or act as an RTSPproxy.

Embodiment 1 of the present invention provides a method for establishingan interactive media session based on IMS as follows.

A1. The terminal initiates an interactive service request to be routedto a MRFC. The interactive service request carries information aboutaddress ports for RTSP connection and address ports for RTP connectionfor media stream delivery.

A2. The MRFC controls the MRFP to interact, and acquires address portsallocated by the MRFP for RTSP connection and RTP connection to theterminal.

A3. The MRFC returns a service request response to the terminal. Theservice request response carries information about address ports forRTSP connection and RTP connection of the MRFP.

A4. The terminal establishes an RTSP connection for interactive controland an RTP connection for delivering a media stream to the MRFPdirectly, based on the received information about address ports.

Since the resource allocation of the MRFP for the RTSP connection andRTP connection is controlled by the MRFC, the MRFC can control andrecord the resource information such as address ports of the MRFP, whichcomplies with the requirement of separating the carrier function andcontrol function in a NGN network environment. Finally, the RTSPconnection is established between the terminal and the MRFP, and theuser can perform operations such as pause, fast forward, rewind, etc.using the RTSP connection.

In the RTSP, the terminal first negotiates the address port for RTPconnection with the application server using a SETUP message, then itstarts to play media stream using a PLAY message. In the RTSP statemachine, if the terminal plays the media stream directly using the PLAYmessage without interaction through a SETUP message, the applicationserver declines the request. In the above method according to embodiment1 of the present invention, since the RTSP connection and RTP connectionare negotiated in the same request, the terminal can play the programdirectly using the PLAY message, without negotiating the RTP connectioninformation using the SETUP message in advance. Thus, the RTSP has to beadjusted appropriately in the above method according to embodiment 1 ofthe present invention, for example, the terminal and application serverno longer negotiate the parameter information for the RTP connection inthe SETUP message; or the terminal is allowed to inform the applicationserver to play the program directly using the PLAY message, withoutdelivering the SETUP message.

In the above method according to embodiment 1, the RTSP and RTPparameter information for the interactive service request and responsecan be carried by the Session Description Protocol (SDP), and the SDPcan be carried by the SIP.

As shown in FIG. 2, a procedure for establishing an interactive mediasession based on IMS according to embodiment 1 of the present inventionis as follows:

101. The terminal initiates an interactive service request to be routedto an application server via a proxy-CSCF and a serving-CSCF. Theinteractive service request also carries information about address portsfor RTSP connection and address port for RTP connection for media streamdelivery, of the terminal. The information may be carried by a SDPmessage;

102. The application server forwards the interactive service request tothe MRFC;

103. The MRFC controls the MRFP to interact, and acquires informationabout address ports allocated by the MRFP for establishing RTSPconnection and RTP connection with the terminal. The MRFP returns theinformation about address ports to the MRFC after allocation. With theinteraction, MRFC acquires information about address ports for RTSPconnection and address ports for RTP connection of the MRFP. Theinteractive protocol can be the H.248 protocol or a combination of theSIP and the eXtensible Markup Language (XML).

104. The MRFC returns a service request response to the applicationserver. Information about address ports for establishing RTSP connectionand RTP connection of the MRFP are included in the service requestresponse.

105. The application server returns the service request response to theterminal via the proxy-CSCF and a serving-CSCF.

106. The terminal establishes the RTSP connection with the MRFP forinteractive control such as fast forward, rewind, and pause, based onthe information about address ports for establishing RTSP connection ofthe MRFP carried in the service request response.

107. The terminal establishes the RTP connection with the MRFP for mediastream delivery, based on the information about address ports forestablishing RTP connection of the MRFP carried in the service requestresponse.

In the above embodiment, the terminal negotiates at the same time theaddress ports for establishing RTSP connection and RTP connection withthe MRFP during interaction of the service request through the IMSsystem. Then, the terminal establishes the RTSP and RTP connectionsdirectly with the MRFP for interactive control and media stream deliveryrespectively.

A method for establishing the interactive media session based on IMSaccording to embodiment 2 of the present invention is described below.

B1. A terminal initiates an interactive service request to be routed toa MRFC. The interactive service request carries information aboutaddress port for RTSP connection of the terminal.

B2. The MRFC controls a MRFP to interact, and acquires an address portallocated by the MRFP for RTSP connection with the terminal.

B3. The MRFC returns a service request response to the terminal. Theservice request response carries information about address ports forRTSP connection of the MRFP.

B4. The terminal establishes an RTSP connection for interactive controlwith the MRFP based on the received information about address ports forRTSP connection.

B5. The terminal sends a SETUP message to the MRFP over the RTSPconnection, and the SETUP message carries information about addressports for establishing RTP connection to deliver a media stream;

B6. After receiving the SETUP message, the MRFP allocates a localaddress port for RTP connection and reports the local address port tothe MRFC;

B7. The MRFP returns a SETUP message response to the terminal, and theSETUP response carries information about the address port for RTPconnection of the MRFP;

B8. The terminal establishes an RTP connection for delivering the mediastream to the MRFP based on the received information about the addressport for RTP connection.

As shown in FIG. 3, a procedure for establishing the interactive mediasession based on IMS according to embodiment 2 of the present inventionis as follows.

201. A terminal initiates an interactive service request to be routed toan application server via a proxy-CSCF and a serving-CSCF. Theinteractive service request also carries information about address portsfor RTSP connection of the terminal. The information about address portsmay be carried by a SDP message, and the SDP message may be carried by aSIP message;

202. The application server forwards the interactive service request toa MRFC;

203. The MRFC controls a MRFP to interact and acquires information aboutaddress ports allocated by the MRFP for establishing RTSP connectionwith the terminal. The MRFP returns information about the allocatedaddress ports to the MRFC after allocation. With the interaction, MRFCacquires the address ports for RTSP connection of the MRFP. The usedinteractive protocol may be the H.248 protocol or a combination of theSIP and the XML;

204. The MRFC returns a service request response to the applicationserver. The information about address ports for RTSP connection of theMRFP is included in the service request response.

205. The application server returns the service request response to theterminal via the proxy-CSCF and the serving-CSCF.

206. The terminal establishes an RTSP connection with the MRFP. Sincethe address port received by the terminal is the address port of theMRFP, the RTSP connection is established between the terminal and theMRFP;

207. After establishing the RTSP connection, the terminal sends a SETUPmessage to the MRFP over the RTSP connection, the SETUP message carriesinformation about the address port for RTP media connection of theterminal;

208 After receiving the SETUP message, the MRFP allocates a localaddress port for RTP connection;

209. After finish allocating the local RTP port, the MRFP reports itsown resource status to the MRFC, including the allocation of ports. Theused interactive protocol may be the H.248 protocol or a combination ofthe SIP and the XML;

210. The MRFP returns a response to the SETUP message, which includesinformation about the address port allocated by the MRFP for RTPconnection;

211. The terminal interacts with the MRFP to communicate other RTSPmessages, such as PLAY messages;

212. The MRFP and terminal establish the RTP connection.

In the above embodiment, the terminal and MRFP negotiate the addressport for RTSP connection first, and then the address port for RTPconnection is negotiated over the RTSP connection; the MRFP reports thestatus of ports and other resource to the MRFC.

It shall be noted that in the above step 206, whether the RTSP messagegoes through AS depends on whether the AS modifies the address port forRTSP, which is similar to the MRFC's operation in embodiment 1.

A method for establishing an interactive media session based on IMSaccording to embodiment 3 of the present invention is described below.

C1. A terminal initiates an interactive service request to be routed toa MRFC. The interactive service request carries information aboutaddress ports for RTSP connection of the terminal;

C2. The MRFC controls a MRFP to interact and acquires information aboutaddress ports allocated by the MRFP for RTSP connection with theterminal;

C3. The MRFC returns a service request response to the terminal. Theservice request response carries information about address ports forRTSP connection of the MRFP. The MRFC allocates a local port for RTSPconnection and returns the local port to the terminal. The MRFC storesthe association between the locally allocated RTSP port and the RTSPport allocated by the MRFP, for the sake of forwarding messages in thefuture;

C4. The terminal establishes an RTSP connection with the MRFC based oninformation about address ports for RTSP connection in the servicerequest response;

C5. After establishing the RTSP connection, the terminal sends a SETUPmessage to the MRFC over the RTSP connection, the SETUP message carriesinformation about address ports for RTP connection, where the RTPconnection is used for media stream delivery;

C6. The MRFC determines whether the MRFP is allowed to continue serviceoperations according to the MRFP's resource status. If it is allowed,the MRFC forwards the SETUP message to the MRFP based on the associationstored in step C3;

C7. After receiving the SETUP message, the MRFP allocates a localaddress port for RTP connection and returns the local port to the MRFC;

C8. The MRFC returns a SETUP message response to the terminal. Thereturned response includes information about address ports allocated bythe MRFP for RTP connection;

C9. Based on the received information about address ports for RTPconnection, the terminal establishes an RTP connection for media streamdelivery between the terminal and the MRFP.

In the above embodiment, the MRFC acts as an RTSP proxy and maps theaddress port allocated by the MRFP for RTSP connection in the servicerequest response into its own address port. Thus, when the terminalreceives the service request response, since the address port in theresponse is the address port of the MRFC, the RTSP connection to theMRFC is established, and thus the SETUP message over the RTSP connectiondelivered by the terminal passes through the MRFC, thereby the MRFC cancontrol the allocation of the port resources of the MRFP. The MRFC doesnot convert information about the address port for RTP connection in theSETUP response message, so the address port contained in the SETUPresponse message received by the terminal is the address port of theMRFP. Thus, the media connection is established directly between theterminal and the MRP after the RTSP message is forwarded by the MRFC.

As shown in FIG. 4, a procedure for establishing an interactive mediasession based on IMS according to embodiment 3 of the present inventionis as follows:

301. A terminal initiates an interactive service request to be routed toan application server via a proxy-CSCF and a serving-CSCF. Theinteractive service request carries information about address ports forRTSP connection of the terminal, where the information may be carried bya SDP message, and the SDP message may be carried by a SIP message;

302. The application server forwards the interactive service request toa MRFC;

303. The MRFC controls a MRFP to interact and acquires an address portallocated by the MRFP for RTSP connection with the terminal. The MRFPreturns information about address ports to the MRFC after allocation.With the interaction, the MRFC acquires information about address portsof the MRFP for RTSP connection. The interactive protocol used can bethe H.248 protocol or a combination of the SIP and the XML;

304. The MRFC returns a service request response to the applicationserver. Information about address ports of the MRFC for the RTSPconnection is included in the service request response. The MRFC acts asan RTSP proxy and allocates a local port for RTSP connection and returnsthe local port to the terminal. The MRFC stores the association betweenthe locally allocated RTSP port and the RTSP port allocated by the MRFP,for the sake of forwarding messages in the future;

305. The application server returns a service request response to theterminal via the proxy-CSCF and the serving-CSCF;

306. The terminal establishes an RTSP connection with the MRFC, based oninformation about the address port for RTSP connection in the servicerequest response;

307. After establishing the RTSP connection, the terminal sends a SETUPmessage to the MRFC over the RTSP connection, the SETUP message carriesinformation about the address port for RTP media connection of theterminal;

308. The MRFC determines whether the MRFP is allowed to continue aservice operation according to the resource status of the MRFP. If it isallowed, the MRFC forwards the SETUP message to the MRFP based on theassociation stored in step 304;

309. After receiving the SETUP message, the MRFP allocates a localaddress port for RTP connection and returns the local address port tothe MRFC;

310. The MRFC returns a response to the SETUP message to the terminal.The returned response includes information about the address portallocated by the MRFP for RTP connection;

311. The terminal interacts with the MRFP for communicating other RTSPmessages, such as PLAY messages, which are routed via the MRFC;

312. The MRFP and the terminal establish an RTP connection.

In the above embodiment, by functioning as a proxy, the MRFC forwardsthe RTSP message between the terminal and the MRFP. In the embodiment,the RTSP message between the terminal and the MRFP is forwarded via theMRFC, and thus the MRFC can control and acquire the address portallocated by the MRFP for RTP connection.

Those skilled in the art shall understand that, the way that the MRFCfunctions as a proxy for the RTSP connection to forward RTSP messagesbetween the terminal and the MRFP is also applicable to otherembodiments of the present invention, such as embodiment 1.

Furthermore, the MRFC can also terminate the RTSP connection and convertthe control information in an RTSP message into other protocol messages,such as an H.248 message or a SIP message, so as to control the MRFP toexert interactive user control. As those skilled in the art shallunderstand, it is not necessary for the MRFP to involve in negotiatingthe RTSP connection parameters in such embodiments.

Similarly, the above implementing modes can also be applied to otherembodiments of the present invention, such as embodiment 1.

A method for establishing an interactive media session based on IMSaccording to embodiment 4 of the present invention comprises:

D1. A terminal initiates an interactive service request to be routed toa MRFC. The interactive service request carries information about anaddress port for RTSP connection of the terminal;

D2. The MRFC controls a MRFP to interact and acquires information aboutan address port allocated by the MRFP for RTSP connection with theterminal;

D3. The MRFC returns a service request response to the terminal. Theservice request response carries information about the address port forRTSP connection of the MRFP. When returning the service requestresponse, the MRFC adds itself to the record-route field in the SIPheader field;

D4. The terminal establishes an RTSP connection with the MRFP based oninformation about the address port for RTSP connection contained in theservice request response. The messages for the establishment of RTSPconnection are encapsulated through SIP messages;

D5. After having established the RTSP connection, the terminalnegotiates with the MRFP address ports for RTP connection by using aSETUP message over the RTSP connection, the SETUP message is forwardedto the MRFC;

D6. If the MRFC allows the terminal and the MRFP to establish an RTPconnection, it forwards the SETUP message to the MRFP;

D7. The MRFP processes the SETUP message and returns a response to theSETUP message to the terminal via the MRFC. The response includesinformation about an address port allocated by the MRFP for RTPconnection. The MRFC records information about the address port;

D8. Based on the received about the address port, the terminalestablishes an RTP connection with the MRFP for media stream delivery.

In the above embodiment, since all the RTSP messages go through theMRFC, the MRFC is capable of acquiring the SETUP message delivered bythe terminal, thus controlling the MRFP to allocate the address port forRTP connection. The RTP media connection is also directly establishedbetween the terminal and the MRFP.

In the above embodiment, the RTSP messages can also be realized byadopting corresponding SIP messages, through extension of the SIPprotocol. In this way, the previously mentionedencapsulating/decapsulating steps no longer involve.

As shown in FIG. 5, a procedure for establishing an interactive mediasession based on IMS according to the fourth embodiment of the presentinvention is as follows:

401. The terminal initiates an interactive service request to be routedto the application server via a proxy-CSCF and a serving-CSCF. Theinteractive service request carries information about an address portfor RTSP connection of the terminal. The information may be carried by aSDP message, and the SDP message may be carried by a SIP message;

402. The application server forwards the interactive service request tothe MRFC;

403. The MRFC controls a MRFP to interact and acquires information aboutan address port allocated by the MRFP for RTSP connection with theterminal. The MRFP returns the information to the MRFC after allocation.With the interaction, the MRFC acquires information about an addressport for RTSP connection of the MRFP. The interactive protocol can bethe H.248 protocol or a combination of the SIP and the XML;

404. The MRFC returns a service request response to the applicationserver. Information about the address port for RTSP connection of theMRFC is included in the service request response. When returning theservice request response, the MRFC adds itself to the record-route filedin the SIP header field, to ensure that the RTSP message to besubsequently encapsulated in a SIP message goes through the MRFC;

405. The application server returns the service request response to theterminal via a proxy-CSCF and a serving-CSCF, the terminal records therouting information in the message header, the proxy-CSCF, theserving-CSCF and the MRFC are included in the routing information;

406. The terminal establishes an RTSP connection with the MRFP, based oninformation about an address port for RTSP connection in the servicerequest response; The messages for the establishment of RTSP connectionare encapsulated through SIP messages;

407. After establishing the RTSP connection, the terminal negotiateswith the MRFP address ports for RTP connection via the SETUP messageover the RTSP connection; the SETUP message is forwarded to the S-CSCFvia the P-CSCF;

408. The serving-CSCF forwards the SETUP message to the MRFC;

409. If the MRFC allows the terminal and the MRFP to establish an RTPconnection, it forwards the SETUP message to the MRFP;

410. The MRFP processes the SETUP message to return a response includinginformation about the address port allocated by the MRFP for RTPconnection.

411. The MRFC records the information about the address port for RTPconnection in the response and forwards the SETUP response to theserving-CSCF;

412. The SETUP response is returned to the terminal via the proxy-CSCF;

413. The terminal notifies the MRFP to play a media stream using a PLAYmessage over the RTSP connection;

414. The MRFP and terminal establish the RTP connection directly.

In the above embodiment, the terminal and the MRFP negotiate addressports for RTSP connection first, and then they negotiate address portsfor RTP connection through the RTSP connection. By encapsulating theRTSP message into a SIP message, the RTSP message goes through the MRFC,and thereby the MRFC can control the MRFP to allocate the address portfor RTP connection.

To ensure that the subsequent RTSP messages go through the IMS system,when negotiating the address port for RTSP connection, the MRFC addsitself to the record-route header field. The terminal encapsulates thesubsequent RTSP message into the SIP message for delivery. Afternegotiating the address port for RTP connection by using the RTSPmessage, the RTP connection is established between the terminal and theMRFP directly.

In the above embodiment, the terminal/MRFP performs a SIP encapsulationtowards the RTSP message, and the MRFP/terminal performs a SIPdecapsulation on the RTSP message. In practice, theencapsulation/decapsulation may also be performed by the MRFC. In thatcase, the SIP message terminates in the MRFC. Then, the MRFC canestablish an RTSP connection with the MRFP, or convert the controlinformation contained in the decapsulated RTSP message to other protocolmessages, such as an H.248 message, thereby controlling the MRFP torealize interactive user control.

Furthermore, in the above embodiments of the present invention, AS canalso function as a proxy for the RTSP connection. In other words, afteracquiring the information about address ports for RTSP connection of theMRFP, the AS allocates a local port for RTSP connection. The AS storesan association between the locally allocated RTSP port and the RTSP portallocated by the MRFP, and returns a service request response to theterminal which carries the information about the address port allocatedby the AS for RTSP connection, for the sake of forwarding messages inthe future. Further, other RTSP messages interacted between the terminaland the MRFP, such as a PLAY message, are forwarded via the AS; the RTPconnection is established between the terminal and the MRFP.

Furthermore, the AS can also terminate the RTSP connection and convertthe interactive media control information in the RTSP message into otherprotocol messages, such as a SIP message, and then send the convertedmessage to the MRFC, thereby controlling the MRFP to realize interactiveuser control.

Furthermore, the terminal can perform a SIP encapsulation/decapsulationon the RTSP message; accordingly, the SIP encapsulation/decapsulationcan be performed by the AS. In that case the SIP message terminates atthe AS. Then, the AS establishes an RTSP connection with the MRFC, orconverts the control information in the decapsulated RTSP message toother protocol messages, such as a SIP message, and sends the convertedmessage to the MRFC, thereby controlling the MRFP to realize interactiveuser control. The connection between the MRFC and MRFP may also be anRTSP connection, or is realized by an H.248 message or a SIP message.

In a practical network deployment, the AS and MRFC can be deployed inthe same network, thus the interface between the AS and MRFC is aninternal interface. In this case, the service quest response carries theinformation about the RTSP address port of the AS or MRFC to theterminal, so as to enable the AS (or MRFC) receive the RTSP message. Theprotocol used between the AS (or MRFC) and MRFP is the RTSP, the H.248protocol or the SIP, which converts the interactive media controlinformation in the received RTSP message into a corresponding protocolmessage to exert control on the MRFP, thereby realizing the interactivemedia control between the user terminal and a media server.

The interactive media session generally includes an RTSP interactivecontrol channel and an RTP media channel. According to embodiments ofthe present invention, the RTSP interactive control channel isestablished at a control layer of the network, thereby ensuring goodcontrol over a network carrier entity by a network control entity, whichconforms to the concept of separating the carrier function and thecontrol function in the NGN. Meanwhile, the media connection isestablished between the terminal and the MRFP, ensuring the mediadelivery efficiency.

In embodiments of the present invention, under the control of the MRFC,the MRFP negotiates the address port for RTP connection to communicatewith the terminal, and establishes the RTP connection with the terminal.

On the above basis, interactive media control information can betransported between the terminal and the AS based on a SIP message. TheAS acquires the interactive media control information from the SIPmessage and converts it to an RTSP message to interact with the mediaserver, thus realizing the interactive media control between the userterminal and the media server. The method of such embodiments applies tothe scenario where the terminal does not support RTSP.

Similarly, a SIP message can be used to communicate interactive mediacontrol information between the terminal and the MRFC, and the MRFCacquires the interactive media control information from the SIP messageand converts it to other messages, such as an H.248 message, to exertinteractive media control over the MRFP, thus realizing the interactivemedia control between the terminal and the MRFP. The method of suchembodiments applies to the scenario where neither the terminal nor thenetwork supports RTSP. The media stream content is provided by the MRFin the IMS network, and the MRFC and MRFP interact with each other usingthe H.248 protocol.

Furthermore, for the scenario where the terminal does not support RTSPand the media stream content is provided by other media server (such asthe previously deployed media stream server which supports the RTSP),the terminal can carry the media interactive control information byextending the SIP message. The IMS network routes the SIP message to theMRF, and the MRF converts the interactive media control information inthe SIP message to an RTSP message so as to exert media control over theinteraction with other media server already deployed in the network.Thereby the media interactive control between the terminal and the finalmedia stream server which provides the service is realized. In the aboveprocedure, the RTP connection is established between the terminal andthe final media server.

Alternatively, the MRFC may support the RTSP to realize the RTSPinteraction. When a SIP message is used to transfer the interactivemedia control information between the terminal and the MRFC, the MRFCacquires the interactive media control information from the SIP messageand converts the interactive media control information to an RTSPmessage, to interact with other media server. Therefore, the interactivemedia control between the terminal and the media stream server whichprovides the service is realized. Here, the MRFC performs the conversionof the media interactive information between the SIP message and theRTSP message.

Alternatively, the MRFP may support the RTSP to realize the RTSPinteraction. A SIP message is used to transfer the interactive mediacontrol information between the terminal and the MRFC. The MRFC acquiresthe interactive media control information from the SIP message andconverts it to an H.248 message to control the MRFP. Under the controlof the MRFC, the MRFP converts the interactive media control informationto an RTSP message, so as to interact with other media server, thusrealizing the interactive media control between the terminal and finalthe media stream server which provides the service. Here, the MRFPperforms the conversion of media interactive information between theH.248 message and the RTSP message.

With reference to FIG. 6, an embodiment of the present invention,provides a media resource control device, comprising: a firstinteractive unit 61 for receiving a request delivered by a terminal, andas a response, returning to the terminal addresses ports forestablishing RTSP and RTP connections with the terminal, according tothe address ports carried in the request for the terminal to establishRTSP and RTP connections; a control unit 62, for controlling the MRFP toallocate address ports for establishing an RTSP connection and an RTPconnection with the terminal, according to the request received by thefirst interactive unit 61.

In a specific implementation, the request may be an interactive servicerequest, which carries address ports of the terminal for establishingthe RTSP and RTP connections. The addresses ports allocated by the MRFPfor establishing connections with the terminal include address ports forRTSP and RTP connections.

In another specific implementation, the request includes the interactiveservice request delivered by the terminal before establishing the RTSPconnection and the SETUP message delivered over the established RTSPconnection. The address port of the terminal for establishing the RTSPconnection is carried in the interactive service request, and theaddress port of the terminal for establishing the RTP connection iscarried in the SETUP message, where the SETUP message is delivered overthe established RTSP connection.

In the above embodiment, the media resource control device is mainlyadapted to control the MRFP to allocate the address ports for the RTSPor RTP connection.

The media resource control device provided by embodiment 2 can furtheract as a proxy to forward the RTSP message between the terminal and theMRFP.

As shown in FIG. 7, the media resource control device according toembodiment 2 of the present invention comprises:

-   -   a first interaction unit 61, adapted to receive a request        delivered by a terminal, and return to the terminal address        ports for establishing connections with the terminal, as a        response;    -   a port allocation unit 63, adapted to allocate a local address        port for RTSP connection, based on the request received by the        first interactive unit 61;    -   a second control unit 62, adapted to control a MRFP to allocate        an address port for establishing an RTP connection with the        terminal, based on the request received by the first interaction        unit 61.

In a specific implementation, the request can be an interactive servicerequest, which carries the address ports of the terminal forestablishing the RTSP and RTP connections. The address ports allocatedby the MRFP for establishing the connections with the terminal includethe address ports for RTSP and RTP connections.

In another specific implementation, the request includes the interactiveservice request delivered by the terminal before establishing the RTSPconnection and the SETUP message delivered over the established RTSPconnection. The address port of the terminal for establishing the RTSPconnection is carried in the interactive service request, and theaddress port of the terminal for establishing the RTP connection iscarried in the SETUP message, where the SETUP message is delivered overthe established RTSP connection.

The media resource control device according to embodiments of thepresent invention may be a MRFC or a function entity independent of theMRFC.

With reference to FIG. 8, an embodiment of the present invention furtherprovides a media resource processing device, comprising: a portallocating unit 81, adapted to allocate, under the control of a MRFC,local address ports for RTSP and/or RTP connections with the terminal; adelivering unit 82, adapted to deliver information about the addressports for RTSP and RTP connections to the MRFC.

In a specific implementation, the local address ports allocated by theport allocating unit 81 include an address port for RTSP connection andan address port for RTP connection. The address ports delivered to theMRFC by the delivering unit 82 include an address port for RTSPconnection and an address port for RTP connection.

In another specific implementation, the local address port allocated bythe port allocating unit 81 is the RTP address port. The delivering unit82 sends information about the address port for RTP connection to theMRFC via the SETUP response message.

In another specific implementation, the local addresses ports allocatedby the port allocating unit 81 include an address port for RTSPconnection and an address for RTP connection. The address portsdelivered to the MRFC by the delivering unit 82 include an address portfor RTSP connection and an address port for RTP connection delivered tothe MRFC through a response to the SETUP message.

A media resource processing device, according to an embodiment of thepresent invention, reports to the MRFC the allocated address ports forthe RTSP and RTP connection. When combined with the media resourcecontrol device according to embodiments of the present invention, themedia resource processing device can establish an RTSP interactivecontrol channel at a control layer of the network, thereby ensuring thecontrol of the network control entity over the network carrier entity,which complies with the requirement of separating the carrier functionand the control function in the NGN network. Meanwhile, the mediaconnection is established between the terminal and the MRFP to ensurethe media delivery efficiency.

The media resource processing device according to embodiments of thepresent invention may be a MRFC or a function entity independent of theMRFC.

It should be noted that in embodiments of the present invention, all andpart of functions of the MRFC can be realized by a functional entityindependent of the MRFC, such a functional entity and the MRFC can bereferred to as media control entity collectively. Similarly, all andpart of functions of the MRFP can be realized by a functional entityindependent of the MRFP, such a functional entity and the MRFP can bereferred to as media carrier entity collectively

Furthermore, the MRFC and MRFP can be combined and referred to as MRF.All and part of functions of the MRF can be realized by a functionalentity independent of the MRF, such a functional entity and the MRF canbe referred to as media server collectively. Those skilled in the artshall understand that the MRF, MRFC and MRFP may correspond to the mediaserver, the control part of the media server and the processing part ofthe media server respectively.

What is claimed is:
 1. A method for establishing an interactive mediasession based on an IP Multimedia Subsystem, comprising: receiving, by amedia control entity, an interactive service request initiated by aterminal; controlling, by the media control entity, a media carrierentity to negotiate an address port for a Real Time Stream Protocol(RTSP) connection and an address port for a Real-time Transport Protocol(RTP) connection to communicate with the terminal; and establishing anRTSP connection for interactive control and an RTP connection for mediastream delivery between the terminal and the media carrier entity. 2.The method of claim 1, wherein, the interactive service request carriesthe terminal's information about an address port for RTSP connection andan address port for RTP connection; and the controlling, by the mediacontrol entity, a media carrier entity to negotiate an address port forRTSP connection and an address port for RTP connection to communicatewith the terminal further comprises: controlling, by the media controlentity, the media carrier entity to interact, and acquiring addressports allocated by the media carrier entity for RTSP connection and RTPconnection with the terminal; and returning, by the media controlentity, a service request response to the terminal, wherein the servicerequest response carries the address ports for RTSP connection and RTPconnection.
 3. The method of claim 1, wherein, the interactive servicerequest carries information about an address port for RTSP connection ofthe terminal; and the controlling, by the media control entity, a mediacarrier entity to negotiate an address port for RTSP connection and anaddress port for RTP connection to communicate with the terminal furthercomprises: negotiating, by the media carrier entity, the address portfor RTSP connection to interact with the terminal, before establishingthe RTSP connection for the interactive control between the terminal andthe media carrier entity; and negotiating, by the media carrier entity,the address port for RTP connection to interact with the terminal, afterestablishing the RTSP connection for the interactive control and beforeestablishing the RTP connection for media stream delivery between theterminal and the media carrier entity.
 4. The method of claim 3, whereinthe negotiating the address port for RTSP connection to interact withthe terminal further comprises: controlling, by the media controlentity, the media carrier entity to interact, and acquiring the addressport allocated by the media carrier entity for the RTSP connection withthe terminal; and returning, by the media control entity, a servicerequest response to the terminal, the service request response carriesinformation about the address port for RTSP connection.
 5. The method ofclaim 3, wherein the negotiating the address port for RTP connection tointeract with the terminal further comprises: sending, by the terminal,a SETUP message to the media carrier entity over the RTSP connection,wherein the SETUP message carries information about an address port forRTP connection of the terminal for media stream delivery; allocating, bythe media carrier entity, a local address port for RTP connection andreporting the local address port to the media control entity, afterreceiving the SETUP message; and returning, by the media carrier entity,a response to the SETUP message to the terminal, wherein the responsecarries information about the address port for RTP connection of themedia carrier entity.
 6. The method of claim 3, wherein the negotiatingthe address port for RTSP connection to interact with the terminalfurther comprises: controlling, by the media control entity, the mediacarrier entity to interact, and acquiring the address port allocated bythe media carrier entity for the RTSP connection with the terminal;returning, by the media control entity, a service request response tothe terminal, wherein the service request response carries informationabout the address port for RTSP connection, and routing information ofthe service request response includes the media control entity.
 7. Amethod for establishing an interactive media session based on IPMultimedia Subsystem, comprising: receiving, by an Multimedia ResourceFunction (MRF), an interactive service request initiating by a terminal;negotiating, by the MRF, an address port for Real Time Stream Protocol(RTSP) connection and an address port for Real-time Transport Protocol(RTP) connection to interact with the terminal; establishing an RTSPconnection for interactive control based on the address port for RTSPconnection between the terminal and a media control entity of the MRF;and establishing an RTP connection for media stream delivery based onthe address port for RTP connection between the terminal and a mediacarrier entity of the MRF.
 8. The method of claim 7, wherein the methodfurther comprises: forwarding, by the media control entity, an RTSPmessage from the terminal to the media carrier entity through the RTSPconnection between the media control entity and the media carrierentity, or converting the RTSP message from the terminal to an H.248message or a SIP message, and then delivering the converted message tothe media carrier entity.
 9. The method of claim 7, wherein the methodfurther comprises: decapsulating by the media control entity, a SIPmessage from the terminal which encapsulates an RTSP message, andforwarding the decapsulated RTSP message to the media carrier entityover the RTSP connection between the media control entity and the mediacarrier entity, or converting the decapsulated RTSP message to an H.248message or a SIP message and then delivering the converted message tothe media carrier entity.
 10. The method of claim 7, wherein, theinteractive service request carries information about an address portfor RTSP connection of the terminal; and the negotiating by the MRF anaddress port for RTSP connection and an address port for RTP connectionto communicate with the terminal comprises: negotiating, by the MRF, theaddress port for RTSP connection to communicate with the terminal,before establishing the RTSP connection for the interactive controlbetween the terminal and the media control entity; and negotiating, bythe media carrier entity, under the control of the media control entity,the address port for RTP connection to communicate with the terminalafter establishing the RTSP connection for the interactive controlbetween the terminal and the media control entity and beforeestablishing the RTP connection for media stream delivery between theterminal and a media carrier entity.
 11. The method of claim 10, whereinthe negotiating by the addresses ports for MRF the RTSP connection tocommunicate with the terminal further comprises: controlling, by themedia control entity, the media carrier entity to interact, andacquiring the address port allocated by the media carrier entity for theRTSP connection with the terminal; allocating, by the media controlentity, a local address port for RTSP connection; and returning, by themedia control entity, a service request response to the terminal,wherein the service request response carries information about theaddress port for RTSP connection of the media control entity.
 12. Themethod of claim 11, wherein the negotiating by the media carrier entitythe address port for RTP connection to communicate with the terminalunder the control of the media control entity comprises: delivering, bythe terminal, a SETUP message to the media carrier entity over the RTSPconnection, the SETUP message carries the terminal's information aboutthe address port for RTP connection; forwarding, by the media controlentity, the SETUP message to the media carrier entity when the mediacarrier entity is allowed to continue a service operation; afterreceiving the SETUP message, allocating by the media carrier entity theaddress port for RTP connection under the control of the media controlentity and returning the address port to the media control entity;returning, by the media control entity, a response to the SETUP messageto the terminal, the response carries information about the address portallocated by the media carrier entity for RTP connection.
 13. The methodof claim 10, wherein: the negotiating by the MRF the address port forRTSP connection to communicate with the terminal comprises: allocating,by the media control entity, the address port for RTSP connection withthe terminal; returning, by the media control entity, a service requestresponse to the terminal, the service request response carriesinformation about the address port for RTSP connection of the mediacontrol entity.
 14. The method of claim 13, wherein the negotiating bythe media carrier entity the address port for RTP connection tocommunicate with the terminal under the control of the media controlentity comprises: delivering, by the terminal, a SETUP message to themedia control entity over the RTSP connection, wherein the SETUP messagecarries the address port for RTP connection of the terminal; converting,by the media control entity, the SETUP message to an H.248 message or aSIP message and delivering the converted message to the media carrierentity when the media carrier entity is allowed to continue the serviceoperation; after receiving the H.248 message or the SIP message,allocating by the media carrier entity the address port for RTPconnection under the control of the media control entity and returningthe allocated address port to the media control entity; and returning,by the media control entity, a response to the SETUP message to theterminal, wherein the response includes the address port for RTPconnection allocated by the media carrier entity.
 15. The method ofclaim 7, wherein: the interactive service request carries informationabout an address port for RTSP connection of the terminal and an addressport for RTP connection; the negotiating by the MRF the address port forRTSP connection and the address port for RTP connection to communicatewith the terminal comprises: controlling, by the media control entity,the media carrier entity to interact, and acquiring the addresses portsallocated by the media carrier entity for RTSP connection and RTPconnection with the terminal; allocating, by the media control entity, alocal address port for RTSP connection; returning, by the media controlentity, a service request response to the terminal, the service requestresponse carries the address port for RTSP connection of the mediacontrol entity and the address port for RTP connection of the mediacarrier entity.
 16. The method of claim 7, wherein the interactiveservice request carries information about an address port for RTSPconnection and an address port for RTP connection of the terminal; thenegotiating by the MRF the address port for RTSP connection and theaddress port for RTP connection to communicate with the terminalcomprises: allocating, by the media control entity, the address port forRTSP connection with the terminal; controlling, by the media controlentity the media carrier entity to interact and acquiring the addressport allocated by the media carrier entity for RTP connection with theterminal; returning, by the media control entity, a service requestresponse to the terminal, the service request response carriesinformation about the address port for RTSP connection of the mediacontrol entity and the address port for RTP connection of the mediacarrier entity.
 17. The method of claim 11, wherein a protocol used bythe media control entity when controlling the media carrier entity tointeract is the H.248 protocol or a combination of the eXtensible MarkupLanguage (XML) and the SIP.
 18. A method for establishing an interactivemedia session based on IP Multimedia Subsystem, comprising: receiving,by a media control entity, an interactive service request initiated by aterminal via an application server; negotiating, by the applicationserver, an address port for Real Time Stream Protocol (RTSP) connectionto communicate with the terminal and establishing an RTSP connectionwith the terminal for interactive control; negotiating, under thecontrol of the media control entity, by a media carrier entity, anaddress port for Real-time Transport Protocol (RTP) connection tocommunicate with the terminal; establishing an RTP connection for mediastream delivery between the terminal and the media carrier entity. 19.The method of claim 18, wherein, the application server converts controlinformation contained in an RTSP message from the terminal to an H.248message or a SIP message and then delivers the converted message to themedia control entity; or the application server establishes an RTSPconnection with the media control entity to forward the RTSP messagefrom the terminal to the media control entity.
 20. A method forestablishing an interactive media session based on IP MultimediaSubsystem, comprising: receiving, by a media control entity, aninteractive service request initiated by a terminal; negotiating, underthe control of the media control entity, by a media carrier entity, anaddress port for Real-time Transport Protocol (RTP) connection tocommunicate with the terminal; establishing an RTP connection for mediastream delivery between the terminal and the media carrier entity;delivering a Session Initiation Protocol (SIP) message to an ApplicationServer (AS) by the terminal, wherein the SIP message carries mediainteractive control information; acquiring, by the AS from the SIPmessage, the media interactive control information and converting themedia interactive control information to an Real Time Stream Protocol(RTSP) message; and interacting, between the AS and a MultimediaResource Function (MRF), through the RTSP messages to exert interactivemedia control between a user and the MRF.
 21. A method for establishingan interactive media session based on IP Multimedia Subsystem,comprising: receiving, by a media control entity, an interactive servicerequest initiated by a terminal; negotiating, by a media carrier entity,an address port for Real-time Transport Protocol (RTP) connection tocommunicate with the terminal under the control of the media controlentity; establishing an RTP connection for media stream delivery betweenthe terminal and the media carrier entity; delivering a SIP message tothe media control entity by the terminal, the SIP message carries mediainteractive control information; acquiring, by the media control entityfrom the SIP message, the media interactive control information andconverting the media interactive control information to an H.248message; and controlling, by the media control entity, the media carrierentity to interact, so as to realize media interactive control throughthe H.248 message.
 22. A method for establishing an interactive mediasession based on IP Multimedia Subsystem, comprising: receiving, by amedia stream server which finally provides service, an interactiveservice request initiated by a terminal; negotiating, under the controlof a controller inside the media stream server, by the media streamserver, an address port for Real-time Transport Protocol (RTP)connection to communicate with the terminal; establishing an RTPconnection for media stream delivery between the terminal and the mediastream server; providing, by the terminal, media interactive controlinformation through a Session Initiation Protocol (SIP) messageextension; sending, by the IMS network, the SIP message to an MultimediaRecourse Function (MRF); and converting, by the MRF, the mediainteractive control information carried in the SIP message to a RealTime Stream Protocol (RTSP) message and exerting media interactivecontrol with a media server already deployed in the network to realizethe media interactive control between the terminal and the media streamserver which finally provides service.
 23. The method of claim 22,wherein the converting by the MRF the media interactive controlinformation carried in the SIP message to an RTSP message and performingmedia interactive control with a media server already deployed in thenetwork comprises: acquiring, by a media control entity, the mediainteractive control information from the SIP message and converting themedia interactive control information to an RTSP message; performing, bythe media control entity, media interactive control with a media serveralready deployed in the network through the RTSP message.
 24. The methodof claim 22, wherein the converting by the MRF the media interactivecontrol information carried in the SIP message to RTSP message andperforming media interactive control with a media server alreadydeployed in the network comprises: acquiring, by the media controlentity, the media interactive control information from the SIP messageand converting the media interactive control information to an H.248message, and controlling the media carrier entity to convert the mediainteractive control information to an RTSP message; and exerting, by themedia carrier entity, the media interactive control with the mediaserver already deployed in the network through the RTSP message.
 25. Asystem for establishing an interactive media session based on IPMultimedia Subsystem, comprising an application server, a media controlentity and a media carrier entity, wherein the media carrier entity isin communication with a terminal, wherein the terminal is adapted toinitiate an interactive service request and establish a Real Time StreamProtocol (RTSP) connection and a Real-time Transport Protocol (RTP)connection; the application server is adapted to process the servicerequest; the media control entity is adapted to control resourceallocation of the media carrier entity; and the media carrier entity isadapted to allocate, under the control of the media control entity,address ports for an RTSP connection and an RTP connection, andestablish the RTSP connection and the RTP connection with the terminal.26. The system of claim 25, wherein, the media control entity is aMultimedia Resource Function Controller (MRFC) or a functional entityindependent of the MRFC; the media carrier entity is a MultimediaResource Function Processor (MRFP) or a functional entity independent ofthe MRFP.
 27. A system for establishing an interactive media sessionbased on IMS Multimedia Subsystem, comprising: an application server, amedia control entity, a media carrier entity, wherein the media carrierentity is in communication with a terminal, wherein the terminal isadapted to initiate an interactive service request and establish a RealTime Stream Protocol (RTSP) connection and a Real-time TransportProtocol (RTP) connection; the application server is adapted to processthe service request; the media control entity is adapted to controlresource allocation of the media carrier entity, and allocate an addressport for RTSP connection to establish an RTSP connection with theterminal; and the media carrier entity is adapted to allocate an addressport for RTP connection under the control of the media control entityand establish an RTP connection with the terminal.
 28. The system ofclaim 27, wherein, the media control entity is a Multimedia ResourceFunction Controller (MRFC) or a functional entity independent of theMRFC; the media carrier entity is a Multimedia Resource FunctionProcessor (MRFP) or a functional entity independent of the MRFP.
 29. Amedia resource control device, comprising: a first interactive unit,adapted to receive a request initiated by a terminal, and as a response,return to the terminal addresses ports for establishing Real Time StreamProtocol (RTSP) and Real-time Transport Protocol (RTP) connections withthe terminal based on address ports of the terminal for establishingRTSP and RTP connections carried in the request; a control unit, adaptedto control a media carrier entity to allocate the address ports forestablishing RTSP and RTP connections with the terminal, based on therequest received by the first interactive unit.
 30. The device of claim29, wherein the request is an interactive service request, and theinteractive service request carries information about the address portfor RTSP connection and RTP connection of the terminal; the addressports allocated by the media carrier entity for establishing connectionswith the terminal comprise the address ports for RTSP connection and RTPconnection.
 31. The device of claim 29, wherein the request includes theinteractive service request delivered by the terminal beforeestablishing the RTSP connection and a SETUP message delivered over theestablished RTSP connection by the terminal; the interactive servicerequest carries information about the address port for RTSP connectionof the terminal, and the SETUP message carries information about theaddress port for RTP connection of the terminal.
 32. A media resourcecontrol device, comprising: a first interactive unit, adapted to receivea request delivered by a terminal, and as a response, return to theterminal address ports for establishing connections with the terminal; aport allocating unit, adapted to allocate a local address port for RealTime Stream Protocol (RTSP) connection based on the request received bythe first interactive unit; a control unit, for controlling a mediacarrier entity to allocate an address port for establishing an Real-timeTransport Protocol (RTP) connection with the terminal, based on therequest received by the first interactive unit.
 33. The device of claim32, wherein the request is an interactive service request, theinteractive service request carries an address port for RTSP connectionand an address port for RTP connection of the terminal.
 34. The deviceof claim 32, wherein the request includes an interactive service requestdelivered before establishing the RTSP connection and a SETUP messagedelivered over the established RTSP connection by the terminal; theinteractive service request carries an address port for RTSP connectionof the terminal, and the SETUP message carries information about anaddress port for RTP connection of the terminal.
 35. A media resourceprocessing device, wherein the device comprises: a port allocating unit,adapted to allocate, under the control of a media control entity, localaddress ports for Real Time Stream Protocol (RTSP) connection andReal-time Transport Protocol (RTP) connection with a terminal; adelivering unit, adapted to deliver the address ports for RTSPconnection and RTP connection to the media control entity.
 36. Thedevice of claim 35, wherein the local address ports allocated by theport allocating unit comprises an address port for RTSP connection andan address port for RTP connection; the address port delivered to themedia control entity by the delivering unit includes the address portfor RTSP connection and the address port for RTP connection.
 37. Thedevice of claim 35, wherein the local address ports allocated by theport allocating unit comprises an address port for RTP connection, thedelivering unit sends the address port for RTP connection to the mediacontrol entity via a response to the SETUP message.
 38. The device ofclaim 35, wherein the local address ports allocated by the portallocating unit comprise an address port for RTSP connection and anaddress port for RTP connection, the address ports delivered to themedia control entity by the delivering unit include the address port forRTSP connection and the address port for RTP connection delivered to themedia control entity via a response to the SETUP message.